Cindrić Ana, Vučković Frano, Murray Aoife, Klarić Thomas S, Alić Ivan, Krištić Jasminka, Nižetić Dean, Lauc Gordan
Genos Glycoscience Research Laboratory, 10000 Zagreb, Croatia.
The Blizard Institute, Barts & The London School of Medicine, Queen Mary University of London, London, E1 2AT, UK.
BBA Adv. 2024 Dec 29;7:100137. doi: 10.1016/j.bbadva.2024.100137. eCollection 2025.
Down syndrome (DS), a genetic condition caused by trisomy 21 (T21), manifests various neurological symptoms, including intellectual disability, early neurodegeneration, and early-onset dementia. N-glycosylation is a protein modification that plays a critical role in numerous neurobiological processes and whose dysregulation is associated with a range of neurological disorders. However, whether N-glycosylation of neural glycoproteins is affected in DS has not been studied. To better understand how T21 affects N-glycosylation during neural differentiation, we utilized an isogenic in vitro induced pluripotent stem cell (iPSC) model of T21 in which both T21 and euploid disomic karyotype (D21) clones were obtained from a single individual with mosaic DS. We comprehensively characterized and compared the total N-glycomes of iPSCs and their neural stem cell (NSC) derivatives. N-glycomics analysis of whole cell lysates was performed using liquid chromatography coupled with tandem mass spectrometry to determine N-glycan structures. Our results show that neural differentiation of iPSCs to NSCs is characterized by an increase in the abundance of complex N-glycans at the expense of minimally processed mannosidic N-glycans. Moreover, we found differences in N-glycosylation patterns between D21 and T21 cells. Notably, the abundance of pseudohybrid N-glycans was significantly higher in T21 cells which also exhibited a significantly lower abundance of a specific hybrid monoantennary fucosylated N-glycan (H6N3F1). Overall, our data define the total N-glycome of both D21 and T21 iPSCs and NSCs and show that T21 already impacts N-glycosylation patterns in the stem cell state in a manner consistent with aberrantly premature neural differentiation of T21 cells.
唐氏综合征（DS）是一种由21号染色体三体（T21）引起的遗传疾病，表现出多种神经症状，包括智力残疾、早期神经退行性变和早发性痴呆。N-糖基化是一种蛋白质修饰，在众多神经生物学过程中起关键作用，其失调与一系列神经疾病有关。然而，DS患者神经糖蛋白的N-糖基化是否受到影响尚未得到研究。为了更好地理解T21如何在神经分化过程中影响N-糖基化，我们利用了一个T21的同基因体外诱导多能干细胞（iPSC）模型，其中T21和整倍体二体核型（D21）克隆均来自一名患有嵌合型DS的个体。我们全面表征并比较了iPSC及其神经干细胞（NSC）衍生物的总N-糖组。使用液相色谱-串联质谱对全细胞裂解物进行N-糖组学分析，以确定N-聚糖结构。我们的结果表明，iPSC向NSC的神经分化特征是复杂N-聚糖丰度增加，而加工最少的甘露糖苷N-聚糖减少。此外，我们发现D21和T21细胞之间的N-糖基化模式存在差异。值得注意的是，T21细胞中假杂交N-聚糖的丰度显著更高，同时还表现出一种特定的杂交单天线岩藻糖基化N-聚糖（H6N3F1）的丰度显著更低。总体而言，我们的数据定义了D21和T21 iPSC及NSC的总N-糖组，并表明T21已经以与T21细胞异常过早神经分化一致的方式影响干细胞状态下的N-糖基化模式。
